string 字符串的零是什么？
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What is the zero for string?
提问by DeanSinaean
func NewKey(c appengine.Context, kind, stringID string, intID int64, parent *Key) *Key
The documentation says :
文档说：
NewKey creates a new key. kind cannot be empty. Either one or both of stringID and intID must be zero. If both are zero, the key returned is incomplete. parent must either be a complete key or nil.
NewKey 创建一个新密钥。种类不能为空。stringID 和 intID 之一或两者必须为零。如果两者都为零，则返回的密钥不完整。parent 必须是完整的键或 nil。
What is the zero for string?
字符串的零是什么？
I tried 0and nil, and I got errors like:
我试过0and nil，我得到了如下错误：
cannot use nil as type string in function argument
回答by Denys Séguret
That's "":
那是""：
var s string
fmt.Println(s=="") // prints "true"
A string cannot be nil (but a *stringcan).
字符串不能为零（但*string可以）。
You can simply test
你可以简单地测试
if stringId=="" {
To pass a zero string in stringID, use
要在 中传递零字符串stringID，请使用
k := NewKey(c, "kind", "", 0, p)
From the specification:
从规范：
When memory is allocated to store a value, either through a declaration or a call of make or new, and no explicit initialization is provided, the memory is given a default initialization. Each element of such a value is set to the zero value for its type: false for booleans, 0 for integers, 0.0 for floats, "" for strings, and nil for pointers, functions, interfaces, slices, channels, and maps.
当通过声明或调用 make 或 new 分配内存来存储值时，并且未提供显式初始化，内存将被赋予默认初始化。这种值的每个元素都被设置为其类型的零值：布尔值为 false，整数为 0，浮点数为 0.0，字符串为""，指针、函数、接口、切片、通道和映射为 nil。
回答by Noypi Gilas
in this case empty string, or you can use NewIncompleteKey()
在这种情况下为空字符串，或者您可以使用 NewIncompleteKey()
